1. Field of Invention
This invention relates generally to flippers and boots, and more particularly to flippers, boots, systems including the flippers and boots, and methods of using the flippers, boots, and systems.
2. Description of Related Art
A user can couple a known flipper to each foot of the user. These known flippers have fins, and when the user kicks in water, for example, the fins can facilitate generating propulsion in the water.
Many known flippers react passively to kicks in water. For example, in many known flippers, the fins maintain generally constant shapes in response to a kick in water. These fins can disadvantageously generate inefficient water flow around the fins. For example, water in the kick path of the fin may be displaced towards lateral sides or a front side of the fin, and such water generally does not contribute to propulsion, disadvantageously reducing efficiency of the flipper.
Other known fins change shape in response to a kick in water, but water in the kick path of these fins generally causes longitudinal center portions of these fins to be displaced away from longitudinal lateral portions of these fins opposite a direction of the kick, causing these fins to curve and become narrower in response to a kick. These fins therefore have reduced widths and thus reduced effective areas during a kick and greater widths when the user is not kicking. Thus, during a kick, effective areas of these fins are disadvantageously reduced. When the user is not kicking, the fin is wider, disadvantageously causing greater drag in the water.
Also, many known flippers have foot pockets for receiving a foot of a user, but these foot pockets are generally integral to the fin and available only in a small number of standard sizes. Therefore, when a user selects a flipper, a user must also select a single foot pocket size of the flipper, often from among a small number of available sizes. Therefore, these foot pockets often do not comfortably fit a foot of a user, and space between the foot and an inside wall of the foot pocket can receive water, disadvantageously adding to drag of the flipper in water and limiting the control of the user over the flipper.